-
Toxins Dec 2021Various species of can produce a number of bioactive compounds, e.g., paralytic shellfish toxins (PSTs), spirolides, gymnodimines, goniodomins, and also uncharacterised... (Review)
Review
Various species of can produce a number of bioactive compounds, e.g., paralytic shellfish toxins (PSTs), spirolides, gymnodimines, goniodomins, and also uncharacterised bioactive extracellular compounds (BECs). The latter metabolites are released into the environment and affect a large range of organisms (from protists to fishes and mammalian cell lines). These compounds mediate allelochemical interactions, have anti-grazing and anti-parasitic activities, and have a potentially strong structuring role for the dynamic of blooms. In many studies evaluating the effects of on marine organisms, only the classical toxins were reported and the involvement of BECs was not considered. A lack of information on the presence/absence of BECs in experimental strains is likely the cause of contrasting results in the literature that render impossible a distinction between PSTs and BECs effects. We review the knowledge on BEC, (i.e., producing species, target cells, physiological effects, detection methods and molecular candidates). Overall, we highlight the need to identify the nature of BECs and urge further research on the chemical interactions according to their ecological importance in the planktonic chemical warfare and due to their potential collateral damage to a wide range of organisms.
Topics: Animals; Dinoflagellida; Marine Toxins
PubMed: 34941742
DOI: 10.3390/toxins13120905 -
International Journal of Molecular... Oct 2022Mesoporous silica nanoparticles (MSNPs) have been widely used for the delivery of different hydrophilic and hydrophobic drugs owing to their large surface area and ease...
Mesoporous silica nanoparticles (MSNPs) have been widely used for the delivery of different hydrophilic and hydrophobic drugs owing to their large surface area and ease of chemical alteration. On the other hand, triphenylphosphonium cation (TPP+) with high lipophilicity has a great mitochondrial homing property that stimulates the internalization of drugs into cells. Therefore, we designed a TPP-modified MSNP to enhance the algicidal activity of our new algicidal agent cyclohexyl-(3,4-dichlorobenzyl) amine (DP92). In this study, algicidal activity was evaluated by assessing the growth rate inhibition of two harmful algal blooms (HABs), and , after treatment with DP92-loaded MSNP or TPP-MSNP and DP92 in DMSO (as control). For , the IC values of TPP-MSNP and MSNP are 0.03 ± 0.01 and 0.16 ± 0.03 µM, respectively, whereas the value of the control is 0.27 ± 0.02 µM. For , the IC values of TPP-MSNP and MSNP are 0.10 ± 0.02 and 0.29 ± 0.02 µM, respectively, whereas the value of the control is 1.90 ± 0.09 µM. Results have indicated that TPP-MSNP efficiently enhanced the algicidal activity of DP92, signifying the prospect of using DP92-loaded TPP-MSNP as an algicidal agent for the superior management of HABs.
Topics: Amines; Dimethyl Sulfoxide; Dinoflagellida; Harmful Algal Bloom; Nanoparticles; Silicon Dioxide
PubMed: 36233203
DOI: 10.3390/ijms231911901 -
Proceedings of the National Academy of... Jan 2021Unicellular flagellated protists are a key element in aquatic microbial food webs. They all use flagella to swim and to generate feeding currents to encounter prey and...
Unicellular flagellated protists are a key element in aquatic microbial food webs. They all use flagella to swim and to generate feeding currents to encounter prey and enhance nutrient uptake. At the same time, the beating flagella create flow disturbances that attract flow-sensing predators. Protists have highly diverse flagellar arrangements in terms of number of flagella and their position, beat pattern, and kinematics, but it is unclear how the various arrangements optimize the fundamental trade-off between resource acquisition and predation risk. Here we describe the near-cell flow fields produced by 15 species and demonstrate consistent relationships between flagellar arrangement and swimming speed and between flagellar arrangement and flow architecture, and a trade-off between resource acquisition and predation risk. The flow fields fall in categories that are qualitatively described by simple point force models that include the drag force of the moving cell body and the propulsive forces of the flagella. The trade-off between resource acquisition and predation risk varies characteristically between flow architectures: Flagellates with multiple flagella have higher predation risk relative to their clearance rate compared to species with only one active flagellum, with the exception of the highly successful dinoflagellates that have simultaneously achieved high clearance rates and stealth behavior due to a unique flagellar arrangement. Microbial communities are shaped by trade-offs and environmental constraints, and a mechanistic explanation of foraging trade-offs is a vital part of understanding the eukaryotic communities that form the basis of pelagic food webs.
Topics: Animals; Dinoflagellida; Feeding Behavior; Flagella; Food Chain; Models, Biological; Movement; Plankton; Predatory Behavior
PubMed: 33431666
DOI: 10.1073/pnas.2009930118 -
Nature Microbiology Jun 2021Alveolata comprises diverse taxa of single-celled eukaryotes, many of which are renowned for their ability to live inside animal cells. Notable examples are apicomplexan...
Alveolata comprises diverse taxa of single-celled eukaryotes, many of which are renowned for their ability to live inside animal cells. Notable examples are apicomplexan parasites and dinoflagellate symbionts, the latter of which power coral reef ecosystems. Although functionally distinct, they evolved from a common, free-living ancestor and must evade their host's immune response for persistence. Both the initial cellular events that gave rise to this intracellular lifestyle and the role of host immune modulation in coral-dinoflagellate endosymbiosis are poorly understood. Here, we use a comparative approach in the cnidarian endosymbiosis model Aiptasia, which re-establishes endosymbiosis with free-living dinoflagellates every generation. We find that uptake of microalgae is largely indiscriminate, but non-symbiotic microalgae are expelled by vomocytosis, while symbionts induce host cell innate immune suppression and form a lysosomal-associated membrane protein 1-positive niche. We demonstrate that exogenous immune stimulation results in symbiont expulsion and, conversely, inhibition of canonical Toll-like receptor signalling enhances infection of host animals. Our findings indicate that symbiosis establishment is dictated by local innate immune suppression, to circumvent expulsion and promote niche formation. This work provides insight into the evolution of the cellular immune response and key steps involved in mediating endosymbiotic interactions.
Topics: Animals; Anthozoa; Coral Reefs; Dinoflagellida; Immunity, Innate; Signal Transduction; Symbiosis
PubMed: 33927382
DOI: 10.1038/s41564-021-00897-w -
Marine Drugs Feb 2020Saxitoxin is an alkaloid neurotoxin originally isolated from the clam in 1957. This group of neurotoxins is produced by several species of freshwater cyanobacteria and... (Review)
Review
Saxitoxin is an alkaloid neurotoxin originally isolated from the clam in 1957. This group of neurotoxins is produced by several species of freshwater cyanobacteria and marine dinoflagellates. The saxitoxin biosynthesis pathway was described for the first time in the 1980s and, since then, it was studied in more than seven cyanobacterial genera, comprising 26 genes that form a cluster ranging from 25.7 kb to 35 kb in sequence length. Due to the complexity of the genomic landscape, saxitoxin biosynthesis in dinoflagellates remains unknown. In order to reveal and understand the dynamics of the activity in such impressive unicellular organisms with a complex genome, a strategy that can carefully engage them in a systems view is necessary. Advances in omics technology (the collective tools of biological sciences) facilitated high-throughput studies of the genome, transcriptome, proteome, and metabolome of dinoflagellates. The omics approach was utilized to address saxitoxin-producing dinoflagellates in response to environmental stresses to improve understanding of dinoflagellates gene-environment interactions. Therefore, in this review, the progress in understanding dinoflagellate saxitoxin biosynthesis using an omics approach is emphasized. Further potential applications of metabolomics and genomics to unravel novel insights into saxitoxin biosynthesis in dinoflagellates are also reviewed.
Topics: Biosynthetic Pathways; Cyanobacteria; Dinoflagellida; Genomics; Metabolomics; Neurotoxins; Protein Biosynthesis; Proteomics; Saxitoxin; Transcriptome
PubMed: 32033403
DOI: 10.3390/md18020103 -
Harmful Algae Nov 2022This paper summarizes the research conducted by the partners of the EU co-funded CoCliME project to ascertain the ecological, human health and economic impacts of...
This paper summarizes the research conducted by the partners of the EU co-funded CoCliME project to ascertain the ecological, human health and economic impacts of Ostreopsis (mainly O. cf. ovata) blooms in the NW Mediterranean coasts of France, Monaco and Spain. This knowledge is necessary to design strategies to prevent, mitigate and, if necessary, adapt to the impacts of these events in the future and in other regions. Ostreopsis proliferations in the Mediterranean have been related to massive mortalities of benthic organisms and to symptoms of respiratory and cutaneous irritation in humans. A six-year epidemiologic study in a Ostreopsis hot spot in Catalonia and the accumulated experience of the French Mediterranean National Ostreopsis Surveillance Network confirm the main effects of these blooms on human health in the NW Mediterranean. The impacts are associated to direct exposure to seawater with high Ostreopsis cell concentrations and to inhalation of aerosols containing unknown irritative chemicals produced under certain circumstances during the blooms. A series of mild acute symptoms, affecting the entire body as well as the ophthalmic, digestive, respiratory and dermatologic systems have been identified. A main remaining challenge is to ascertain the effects of the chronic exposure to toxic Ostreopsis blooms. Still, the mechanisms involved in the deletereous effects of Ostreopsis blooms are poorly understood. Characterizing the chemical nature of the harmful compounds synthesized by Ostreopsis as well as the role of the mucus by which cells attach to benthic surfaces, requires new technical approaches (e.g., metabolomics) and realistic and standardized ecotoxicology tests. It is also necessary to investigate how palytoxin analogues produced by O. cf. ovata could be transferred through the marine food webs, and to evaluate the real risk of seafood poisonings in the area. On the other hand, the implementation of beach monitoring and surveillance systems in the summer constitutes an effective strategy to prevent the impacts of Ostreopsis on human health. In spite of the confirmed noxious effects, a survey of tourists and residents in Nice and Monaco to ascertain the socioeconomic costs of Ostreopsis blooms indicated that the occurrence of these events and their impacts are poorly known by the general public. In relationship with a plausible near future increase of Ostreopsis blooms in the NW Mediterranean coast, this survey showed that a substantial part of the population might continue to go to the beaches during Ostreopsis proliferations and thus could be exposed to health risks. In contrast, some people would not visit the affected areas, with the potential subsequent negative impacts on coastal recreational and touristic activities. However, at this stage, it is too early to accurately assess all the economic impacts that a potentially increasing frequency and biogeographic expansion of the events might cause in the future.
Topics: Humans; Marine Toxins; Dinoflagellida; Seawater; Seasons; Socioeconomic Factors
PubMed: 36344192
DOI: 10.1016/j.hal.2022.102320 -
Genomics Jul 2022Corals should make excellent models for cross-kingdom research because of their natural animal-photobiont holobiont composition, yet a lack of studies and experimental...
Corals should make excellent models for cross-kingdom research because of their natural animal-photobiont holobiont composition, yet a lack of studies and experimental data restricts their use. Here we integrate new full-length transcriptomes and small RNAs of four common reef-building corals with the published Cladocopium genomes to gain deeper insight into gene regulation in coral-Symbiodiniaceae holobionts. Eleven novel Symbiodiniaceae miRNAs get identified, and enrichment results of their target genes show that they might play a role in downregulating rejection from host coral cells, protecting symbiont from autophagy and apoptosis in parallel. This work provides evidence for the early origin of cross-kingdom regulation as a mechanism of self-defense autotrophs can use against heterotrophs, sheds more light on coral-Symbiodiniaceae holobionts, and contributes valuable data for further coral research.
Topics: Animals; Anthozoa; Coral Reefs; Dinoflagellida; MicroRNAs; Symbiosis; Transcriptome
PubMed: 35714829
DOI: 10.1016/j.ygeno.2022.110404 -
Analytical Chemistry Oct 2022Dinoflagellate-derived polyketides are typically large molecules (>1000 Da) with complex structures, potent bioactivities, and high toxicities. Their discovery suffers...
Dinoflagellate-derived polyketides are typically large molecules (>1000 Da) with complex structures, potent bioactivities, and high toxicities. Their discovery suffers three major bottlenecks: insufficient bioavailability, low-yield cultivation of producer organisms, and production of multiple highly related analogues by a single strain. Consequently, the biotechnological production of therapeutics or toxicological standards of dinoflagellate-derived polyketides is also hampered. Strategies based on sensitive and selective techniques for chemical prospection of dinoflagellate extracts could aid in overcoming these limitations, as it allows selecting the most interesting candidates for discovery and exploitation programs according to the biosynthetic potential. In this work, we assess the combination of data-dependent liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-HRMS) and molecular networking to screen polyol polyketides. To demonstrate the power of this approach, we selected dinoflagellate since it is commonly used as a biotechnological model and produces amphidinols, a family of polyol-polyene compounds with antifungal and antimycoplasmal activity. First, we screened families of compounds with multiple hydroxyl groups by examining MS profiles that contain sequential neutral losses of water. Then, we clustered MS spectra by molecular networking to facilitate the dereplication and discovery of amphidinols. Finally, we used the MS fragmentation behavior of well-characterized luteophanol D as a model to propose a structural hypothesis of nine novel amphidinols. We envision that this strategy is a valuable approach to rapidly monitoring toxin production of known and unknown polyol polyketides in dinoflagellates, even in small culture volumes, and distinguishing strains according to their toxin profiles.
Topics: Antifungal Agents; Dinoflagellida; Polyenes; Polyketides; Polymers; Water
PubMed: 36190828
DOI: 10.1021/acs.analchem.2c02185 -
Microbiological Research Dec 2022While bacterial and archaeal communities of sponges are intensively studied, given their importance to the animal's physiology as well as sources of several new... (Review)
Review
While bacterial and archaeal communities of sponges are intensively studied, given their importance to the animal's physiology as well as sources of several new bioactive molecules, the potential and roles of associated protists remain poorly known. Historically, culture-dependent approaches dominated the investigations of sponge-protist interactions. With the advances in omics techniques, these associations could be visualized at other equally important scales. Of the few existing studies, there is a strong tendency to focus on interactions with photosynthesizing taxa such as dinoflagellates and diatoms, with fewer works dissecting the interactions with other less common groups. In addition, there are bottlenecks and inherent biases in using primer pairs and bioinformatics approaches in the most commonly used metabarcoding studies. Thus, this review addresses the issues underlying this association, using the term "microeukaryome" to refer exclusively to protists associated with an animal host. We aim to highlight the diversity and community composition of protists associated with sponges and place them on the same level as other microorganisms already well studied in this context. Among other shortcomings, it could be observed that the biotechnological potential of the microeukaryome is still largely unexplored, possibly being a valuable source of new pharmacological compounds, enzymes and metabolic processes.
Topics: Animals; Archaea; Bacteria; Biotechnology; Dinoflagellida; Phylogeny; Porifera
PubMed: 36183422
DOI: 10.1016/j.micres.2022.127210 -
Toxins Jan 2020Recurrent blooms of cf. have been reported in Brazil and the Mediterranean Sea with associated ecological, and in the latter case, health impacts. Molecular data...
Recurrent blooms of cf. have been reported in Brazil and the Mediterranean Sea with associated ecological, and in the latter case, health impacts. Molecular data based on the D1-D3 and D8-D10 regions of the LSU rDNA and ITS loci, and the morphology of . cf. isolates and field populations from locations along the Brazilian tropical and subtropical coastal regions and three oceanic islands are presented. Additional ITS sequences from three single cells from the tropical coast are provided. Toxin profiles and quantities of PLTX and their analogues; OVTXs; contained in cells from two clonal cultures and two field blooms from Rio de Janeiro were investigated. Morphology was examined using both light and epifluorescence microscopy. Morphometric analysis of different strains and field populations from diverse locations were compared. Molecular analysis showed that six of the seven sequences grouped at the large "Atlantic/Mediterranean/Pacific" sub-clade, while one sequence branched in a sister clade with sequences from Madeira Island and Greece. The toxin profile of strains and bloom field samples from Rio de Janeiro were dominated by OVTX-a and -b, with total cell quotas (31.3 and 39.3 pg cell) in the range of that previously reported for strains of . cf. .
Topics: Brazil; Dinoflagellida; Marine Toxins; Phylogeny
PubMed: 31979144
DOI: 10.3390/toxins12020070